Do you have SS amp?
If you do and after tube swapping or replacements the problem's still percists, measure DC Voltage at binding posts of amp or speakers(have speakers connected) while the unit is off.
If the level is larger than 100mV, contact manufacturer. If you're DIY than probably output caps are at fault.
If you do and after tube swapping or replacements the problem's still percists, measure DC Voltage at binding posts of amp or speakers(have speakers connected) while the unit is off.
If the level is larger than 100mV, contact manufacturer. If you're DIY than probably output caps are at fault.